The integumentary system is the largest organ of the body, making up 7% of total body weight. It has several key functions, including protection from injury, infection, water loss, temperature control, waste removal, sensory information gathering, and vitamin D activation. The integumentary system has two main layers - the epidermis and dermis. The epidermis contains keratinocytes and has no blood vessels or nerves, while the dermis contains many blood vessels, nerves, sweat glands, and oil glands. Injuries to the integumentary system can range from first degree burns affecting just the epidermis to third degree burns penetrating the full thickness of the skin. Diseases of

1. 6th Grade ScienceIntegumentary System

2. I. GeneralSize1. Largest organ2. 7% of body weightB. Function 1. Protection from injury2. Protection from infection3. Protection from water loss4. Control body temperature5. Remove waste6. Gather information about the world7. Activation of Vitamin D

3. C. LayersEpidermis (Keratinocytes)i. Outer layersii. No blood or nervesiii. Cells die and are replaced every two weeksiv. Constant outward flow protects from bacteriav. Layers prevent water lossvi. Produces melanin (protect from UV damage)

5. 2. Dermisi. Many blood vessels and nervesii. Sweat glands – Cool bodyiii. Oil glandsa. Hair and skin healthb. Chemical signalsiv. Hair

6. D. Special Structures1. Nails

7. 2. Hairi. ArrectorPili Muscle (Fright or cold)

8. II. InjuriesA. Classified by severity1. First degree burn – only epidermis is damaged2. Second degree burn – upper part of dermisi. Blisters appearii. Skin heals with scarring3. Third degree burn – consume thickness of skini. Burned area appears white, red, or blackenedii. Often little pain noticed as nerves are all dead

9. III. DiseasesCancer (sun exposure) 1. Basal cell carcinoma – most common 2. Squamouscell carcinoma 3. Melanoma –Most dangerous typeB. Age spotsC. Smoke damage